Indonesia, Malaysia, Thailand, Cambodia, Vietnam, Laos, Philippines, Myanmar, Singapore

Monday, May 9, 2011

Dengue Fever in Southeast Asia

The Asian Tiger Mosquito

Dengue fever is one of the most serious mosquito-spread diseases in the tropics. The World Health Organization reports the incidence of dengue has grown dramatically around the world in recent decades. Some 2.5 billion people – two fifths of the world's population – are now at risk from dengue. WHO currently estimates there may be 50 million dengue infections worldwide every year. Southeast Asia and the Western Pacific are the most seriously affected. All travelers to Southeast Asia should be familiar with the signs and symptoms of this disease.

An estimated 500 000 people with DHF require hospitalization each year, a very large proportion of whom are children. About 2.5% of those affected die. Without proper treatment, DHF fatality rates can exceed 20%. Wider access to medical care from health providers with knowledge about DHF - physicians and nurses who recognize its symptoms and know how to treat its effects - can reduce death rates to less than 1%.

Dengue is a cover name for four different but related viruses and is transmitted by the bite of an Aedes mosquito, also known as the striped or tiger mosquito, that is infected with any one of the four dengue viruses. Dengue requires emergency medical treatment as it can develop into dengue shock syndrome, also known as dengue haemorrhagic fever, which has a 6%-30% fatality rate. Dengue is only spread through the mosquito vector—you cannot contract dengue from an infected person. After being bitten by a mosquito carrying the virus, the incubation period ranges from three days to two weeks before the signs and symptoms of dengue appear. The onslaught of the infection can last a week to two weeks in most cases with full recovery sometimes taking as long as six to eight weeks.

Because there is no vaccine for dengue, preventing transmissions is the only way to prevent infection.  Therefore, use of mosquito netting and DEET or other insect repellents is recommended especially in areas where dengue is reported.  The aedes mosquito are most active in the mornings and evenings rather at night which makes daytime mosquito protection especially important.

Dengue generally starts with flu-like signs and symptoms such as chills, headache, pain upon moving the eyes, and low backache. It usually quickly develops into severe joint-pain, a sign that earned it its other moniker, "breakbone fever." This painful aching in the legs and joints occurs during the first hours of illness.
A fever quickly sets in, with temperatures as high as 104 F (40 C), with relative low heart rate (bradycardia) and low blood pressure (hypotension). 
Travelers may not always be able to detect just how high the temperature is or be able to detect low blood pressure and heart rate. The next signs are more definitive and if they occur before medical treatment has been sought then one should immediately seek emergency medical attention. The eyes become reddened and a flushing or pale pink rash comes over the face and then disappears. These are classic signs that one may be infected with one of the dengue viruses and should not be ignored. 

As treatment may require medical evacuation in some locations in Southeast Asia where local treatment is inadequate, acting quickly is of the essence. Bangkok, Singapore, and Kuala Lumpur are recommended treatment locations; Jakarta, Phnom Penh, Siem Reap, and Bali also offer acceptable medical facilities. With treatment, the fatality rate of dengue fever is just under 1%.

Dengue haemorrhagic fever (DHF) is a potentially deadly complication that is characterized by high fever, often with enlargement of the liver, and in severe cases circulatory failure. DHF is also called Philippine, Thai, or Southeast Asian hemorrhagic fever and dengue shock syndrome. The illness often begins with a sudden rise in temperature accompanied by facial flush and other flu-like symptoms. Manifestations include headache, fever, rash, and evidence of hemorrhage in the body. Petechiae (small red or purple blisters under the skin), bleeding in the nose or gums, black stools, or easy bruising are all possible signs of hemorrhage. The fever usually continues for two to seven days and can be as high as 41°C, possibly with convulsions and other complications.

In moderate DHF cases, all signs and symptoms abate after the fever subsides. In severe cases, the patient's condition may suddenly deteriorate after a few days of fever; the temperature drops, followed by signs of circulatory failure, and the patient may rapidly go into a critical state of shock and die within 12 to 24 hours, or quickly recover following appropriate medical treatment.

Patients with DHF must be monitored closely for the first few days since shock may occur or recur precipitously (dengue shock syndrome). Cyanotic (bluish) patients are given oxygen. Vascular collapse (shock) requires immediate fluid replacement. Blood transfusions may be needed to control bleeding. Patients may need platelet infusions and like most dengue patients may require an IV to ensure hydration.


Because dengue fever is caused by a virus, there is no specific medicine or antibiotic to treat it. For typical dengue, the treatment is purely concerned with relief of the symptoms (symptomatic). Use of acetylsalicylic acid (e.g. aspirin) and non steroidal anti-inflammatory drugs (e.g. Ibuprofen) is not recommended as it can complicate the hemorrhaging associated with the disease. Instead, Tylenol or other fever-reducing drugs can be administered and codeine can be used to treat the pain. In severe cases, IVs, oxygen administration and blood infusions may also be used in combating the worst complications of the disease.

  • Sudden and abrupt onset
  • May go up to 39.5-41.4°C
  • Lasts for about 1-7 days, then fades away for 1-2 days
  • It soon recurs with secondary rashes which is usually not as severe as before
  • Fever is usually accompanied by headache in front portion of head or behind the eyes
Muscular (Myalgia) or bone pain:
  • Occurs after onset of fever
  • Affects legs, joints, and lumbar spine
  • Usually the pain gets severe after its onset
  • The pain may last for several weeks even after the fever has subsided
  • Pain is usually absent in DHF/DSS
Other symptoms:
  • Nausea and vomiting
  • Loss of appetite
  • Increased sensation to touch
  • Change in taste sensation
  • Symptoms maybe milder in children than in adults
  • The acute phase of illness can last for 1 week followed by a 1 to 2 week period of recovery period that is characterized by weakness, malaise and loss of appetite.
  • Rash - red and white patchy rashes
Dengue Hemorrhagic Fever / Dengue Shock Syndrome
Initial stages of the disease resembles symptoms of dengue fever. However fever subsidies after 2 to 7 days followed by signs and symptoms of:
  • Restlessness
  • Signs of circulatory failure
  • Bleeding or hemorrhagic manifestations including:
    • Skin bleeds that appear as blotchy red patches called Petechiae
    • Bleeding from Nose or Epistaxis
    • Black stools
    • Easily bruising
    • Bleeding from gums
    • Bleeding from Stomach - appearing as blood in the vomit
    • Decrease in the blood platelet count (Thrombocytopenia)
    • Leakage of plasma from vascular compartment leading to increased blood concentration and manifestations of shock.

As a reminder to travelers, it is always a good idea to write down or put into your phone the local emergency medical contact number.  However, hotels, guesthouses and locals can usually direct you to the best medical care facilities in the area.


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